GB2484771 discloses a fixing device for securing into a hole in plasterboard, comprising: a body having an anchor receiving aperture, and a passage that extends within the body, spaced from the anchor receiving aperture; a shaft provided within the passage, the shaft being rotatably movable, independent of axial movement, within the passage; and retaining means coupled to the shaft and configured to be movable between an extended position, in which the fixing device is retainable in said hole, and a retracted position, in which the fixing device is removably insertable into said hole.
The fixing device may be operated, once it has been inserted into a hole in a structure, by moving the retaining member to the extended position. For instance, a hole may be drilled in a plasterboard structure for insertion of the fixing device axially therein. The fixing device may be inserted into the hole from the front face of the plasterboard, such that the retaining members are behind the rear face of the plasterboard. Rotating the shaft causes the retaining member to move from its retracted position (i.e. its ambush position, in which it sits within the axial profile of the body) to its extended position (in which it projects radially away from the body). In the extended position, the retaining member therefore substantially inhibits movement of the fixing device through the hole in the plasterboard, thus preventing removal of the fixing device from the front face of the structure. If the fixing device is recessed within the hole (either by over-insertion or if the body has a depth less than the thickness of plasterboard), then the retaining member can be drawn tight against the rear face of the plasterboard by fixing a plate (which could be, for instance, part of a hook or bracket for attachment to the plasterboard) to the front face with an anchor, received within the anchor receiving aperture. Specifically, the anchor may draw the plate and the fixing device toward each other, thereby drawing the retaining member tight against the rear face, and drawing the plate tight against the front face.
Different thicknesses of plasterboard require insertion of this form of fixing device to different depths. However, skill is required in determining this depth and accidental over-insertion of the fixing device, such that the device is lost into a cavity behind the plasterboard, is a common risk.